OK so there is 3-4 databases for you to do transaction log backups of. They are changing/adding 100 records, is that per day? per hour? per week? How important is the data? These answers will decide how frequently you will want to back them up.

The transaction log backups will be backed up to a different server/different physical disk right?

You will only need the transaction log backups if the drive containing the transaction log suddenly fails.

If this happens and you have no transaction log backups then you will lose the data from that day (assuming you have nightly full backups).

If you backup the log every 1 hour then you lose data up to 60 minutes old.

If you backup the log every 15 minutes then you only lose up to 15 minutes of data.

How important the data is will decide how regular you do them. Many of our databases at work are SIMPLE meaning that we can only return to the state from the day before; I guess because they deemed that an acceptable amount of loss.

That said; if you will keep the backups on the same server, on the same disk (database and backups both on D: or the backups on a logical E: partition) then there's no need to backup with such frequency and you can just schedule it for once per night. This setup isn't recommended though because if the disk fails you will lose everything. This is why it's better to backup to a different server. But because you have Enterprise Edition I guess your workplace should have plenty of servers you can use to keep backups on.